DESCRIPTION (Applicant's Description) While long-term lipotrope (choline, methionine, folic acid, and vitamin B-12 deficiency enhances the activity of several hepatocarcinogens, the effect of these nutrients upon mammary cancer is not well understood. Altered DNA methylation may contribute to the increased development of carcinoma because of its role in gene expression. However, DNA damage is also an early consequence of methyl depletion, and it is an important factor contributing to cell death. We hypothesize that lipotrope deficiency may have a significant effect on the inhibition of cell growth and on the induction of cell death in the human breast cancer cell line, MCF-7. The experiment will examine the response of the MCF-7 cell line to lipotrope modification, focusing on the suppression of cell growth mediated by lipotrope deficiency. Specific aims are 1) to confirm if growth inhibition is induced by lipotrope deficiency in the MCF-7 cell line; 2) to investigate if lipotrope deficiency induces DNA fragmentation with subsequent morphological appearance of cell death (apoptosis); 3) to examine if lipotropes mediate changes in the expression of certain genes involved in the regulation of the cell cycle and apoptosis (bcl-2); and 4) to identify if apoptosis induced by lipotrope deficiency is a p53-dependent or p53-independent process. The overall goal of this study is to develop a better understanding of the role of lipotropes in the prevention and treatment of cancer. Data from the proposed research will establish a link between methyl donors, cell growth and cell death, and gene expression which will be of significance to the development of dietary components and chemotherapeutic agents that may suppress and treat human breast cancer.